Efficient rearing of livestock and other animals is dependent upon ensuring high growth rates, feed intake, productivity, and reproductive success. Some of the greatest threats to animal growth and productivity include bacterial and fungal infections, and oxidative stress. Hormones and antibiotics are commonly used as productivity and growth promoters in animals. For example, antibiotics, such as coccidiostats, are often administered regularly in subtherapeutic doses to promote animal health and growth. However, these approaches have garnered significant outcry from scientific and social communities over the past decade.
Subtherapeutic antibiotics have been linked to pathogenic antibiotic resistance in animals, and their use as animal feed additives and growth promoters are banned in many countries. Similarly, animal hormonal supplements have been linked to detrimental side effects in animals as well as public health concerns for humans. Further, the need for alternatives to subtherapeutic antibiotics and hormonal growth promoters is readily recognized by the significant economic incentive to market animal products as “natural”, “organic”, “hormone-free” and “antibiotic-free”.
Essential oils such as oregano, thyme, and cinnamon have been disclosed in the art primarily as flavoring or odorizing agents. Essential oils have in some instances been disclosed as pharmaceuticals for medical and veterinary uses, yet the efficacy and compatibility of multi-essential oil blends are unpredictable and often undesirable. For example, U.S. Pat. No. 6,106,838 teaches that essential oils of thyme and oregano exhibit antagonist effects when combined for pharmaceutical uses.